19th May 2009
Make better use of slurry and meet NVZ regulations This year’s NVZ regulations will require many livestock farms to increase their slurry storage capacity. Andy Collings visited an East Yorkshire farming company to see how it plans to profit from such changes Like many other farming businesses, JSR Farming has had to look closely at its slurry storage system to ensure there is sufficient capacity to hold the six months’ supply required by recent changes to NVZ rules. And, in doing so, it plans to use the required capacity increase to ensure better use is made of the resource. The material – all 30m litres of it – is produced by the Driffield company’s three pig units, which have more than 3000 sows and progeny – in all about 18,500 pigs.
Company director, Philip Huxtable has endeavoured to ensure that slurry and FYM produced in straw bedded areas make a major contribution to reducing the farms’ fertiliser costs and is fully used on the farms’ arable areas, which run to 3500ha (8500 acres). “I estimate that the value of slurry in terms of its NPK content is worth about £300/ha and that of FYM to be £200/ha,” he explains.
The more solid FYM is normally spread in the autumn and ploughed in before the ground is planted with a second wheat crop. Slurry is first separated using a Bauer screw-type auger and is held in a storage tank while the resulting solids are mixed with the straw-based FYM.
Most of the slurry is then spread using an umbilical-fed 24m dribble system and, so that its fertiliser contribution can be recorded, it is analysed for NPK content and the actual volume spread monitored by an in-line flow meter.
The aim is to put about half of a cereal crop’s nitrogen requirement on with slurry and then top up with inorganic fertiliser using a Yara N-sensor to help compensate for any rate fluctuations or missed areas.
Inevitably, it has always been the fields closest to the pig units which have received the slurry dressings and fields further away have not been able to benefit from such treatments. As a result, more distant fields tend to suffer with low P and K indices.
“Key to the system is to site new slurry stores on the outlying farms from where it becomes more economical for tankers to operate and spread slurry on the surrounding fields,” he says. “Fields where we have managed to apply slurry to have all recorded wheat yield increases of about 0.7t/ha year on year – and this is clearly a major incentive for this new initiative.”
Two new stores have now been built – one with a 720cu m capacity and another with 1350cu m. Both stores have been provided with a “lid” following concerns about rainwater entering the tanks.
“Where 750mm of rain falls each year, this puts a depth of 0.75m into a tank. If the tank was 20m diameter, this equates to 225cu m of rainwater – an extra dozen or more loads for a tanker to pump, transport and spread,” says Mr Huxtable.
The lids are the first of their kind to be used in the UK and are sourced from Dutch company Genap, which makes the Airhat store cover. Made of a tough polythene-type material, the sheet is spread across the top of the stores and anchored down around the edge by a network of ropes. The clever bit is that there is a small air pump which inflates the sheet to create a neat dome-shape for the rain to run off.
There is one more part of the plan to instigate – the purchase of a large capacity slurry tanker. A tri-axle, 23cu m Joskin tanker will have, he says, three roles to play:
During the winter it will transport slurry from pig units to stores placed several miles away. This will free up space in the stores closer to the pig units.
Throughout the spring the tanker will spread slurry on outlying fields using a 24m dribble bar system.
In autumn, the boom will be replaced with a 5.5m cultivator/ injector unit, which will assist with cultivation and apply slurry in preparation for the next crop to be planted – such as oilseed rape.
Farmers Weekly 1 May 2009
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